Implement multiple 'auto' feature from Concepts TS.

	* parser.c (cp_parser_type_id_1): Allow 'auto' if -fconcepts.
	(cp_parser_template_type_arg): Likewise.
	(get_concept_from_constraint): Split out most logic to...
	* constraint.cc (placeholder_extract_concept_and_args): ...here.
	(equivalent_placeholder_constraints, hash_placeholder_constraint): New.
	* cxx-pretty-print.c (pp_cxx_constrained_type_spec): New.
	* cxx-pretty-print.h: Declare it.
	* error.c (dump_type) [TEMPLATE_TYPE_PARM]: Call it.
	* pt.c (is_auto_r, extract_autos_r, extract_autos, auto_hash): New.
	(type_uses_auto): Use is_auto_r.
	(do_auto_deduction): Handle multiple 'auto's if -fconcepts.
	* typeck.c (structural_comptypes) [TEMPLATE_TYPE_PARM]: Compare
	constraints.

From-SVN: r229629

1 files changed, 20 insertions, 0 deletions

diff --git a/gcc/cp/cxx-pretty-print.c b/gcc/cp/cxx-pretty-print.c
index ea6b4c5..72bbfc5 100644
--- a/gcc/cp/cxx-pretty-print.c
+++ b/gcc/cp/cxx-pretty-print.c
@@ -2195,6 +2195,26 @@ pp_cxx_canonical_template_parameter (cxx_pretty_printer *pp, tree parm)
   pp_cxx_end_template_argument_list (pp);
 }
 
+/* Print a constrained-type-specifier.  */
+
+void
+pp_cxx_constrained_type_spec (cxx_pretty_printer *pp, tree c)
+{
+  tree t, a;
+  placeholder_extract_concept_and_args (c, t, a);
+  pp->id_expression (t);
+  if (TREE_VEC_LENGTH (a) > 1)
+    {
+      pp_cxx_begin_template_argument_list (pp);
+      tree args = make_tree_vec (TREE_VEC_LENGTH (a) - 1);
+      for (int i = TREE_VEC_LENGTH (a) - 1; i > 0; --i)
+	TREE_VEC_ELT (args, i-1) = TREE_VEC_ELT (a, i);
+      pp_cxx_template_argument_list (pp, args);
+      ggc_free (args);
+      pp_cxx_end_template_argument_list (pp);
+    }
+}
+
 /*
   template-declaration:
      export(opt) template < template-parameter-list > declaration